1. Field of the Invention
This invention relates to a press brake and more particularly to a press brake male die assembly for precision positioning of a workpiece in the press brake.
2. Description of the Prior Art
As is well known in the art, press brakes utilize a fixedly mounted female die and a reciprocally movable male die for folding, bending or otherwise forming work pieces, such as sheet metal, in two dimensions only. For example, such machines are often used to form elongated uniform channels, gutters, and other configurations which require that the workpiece be bent at various places thereon. Forming operations of this type oftentimes require that several individual sequential steps be performed on a single sheet of material. For example, complex cross sectional products may be developed by employing several different die sets, or by repeated use of a single die set, to form the product section-by-section, such as a sheet of uniformly corrugated configuration.
In the way of a simple example of such a multistep workpiece forming operation, consider the formation of a four-sided pan-shaped box from a flat sheet of material. First, the flat sheet is suitably cut and notched such as in a punch press, at each of its corners and then each side is individually and sequentially bent along a bend or forming centerline to provide the four upstanding sidewalls of the box.
In using a press brake for operations of the above described type, it is extremely important that the workpiece be exactly positioned between the male and female die set. When several individual and sequential operations are accomplished on a single workpiece, a plurality of related positions must be established and accurately followed if the desired configuration of the finished product is to be achieved.
Press brakes usually incorporate gages or guide members, sometimes referred to as fences, for receivably engaging the edge of a workpiece to limit the extent to which the workpiece may be inserted between the die set. The use of such gages or fences is reasonably accurate, however, if a slight positioning error is made on one of the first in a series of sequential operations, the error will be repeated and enlarged as the subsequent position related operations are accomplished.
Therefore, a new and improved method and apparatus for precision positioning of a workpiece in a press brake is needed to overcome some of the shortcomings and drawbacks of the prior art.